I have about a week's worth of GS experience (and virtually no programming skill) and so I don't think i'm the right guy for the job - it's too frustrating and my expertise is in music and animation....

What skipnosis would have to do first, I think, is provide a full game design document. This would make clear what is expected of the guy that ends up making this for him.

Of course, you can't foresee every eventuality, so there'd have to be a clause that states that changes can be made, but limited changes, that do not require a complete re-write of what's already been done.

For example: If there are 20 levels, and 15 enemies detailed in the GDD, then it might be reasonable to ask for one more level and a couple of enemies to be added. Asking for double those would be out of line.

It's about managing expectations. Timelines would have to be agreed, a fee agreed, contracts drawn up.

It's all very very messy, which is why I suggested Skipnosis give it a go first.